The present invention relates to a smoke pollution device for a tunnel kiln, for improving smoke emissions of a brick kiln, for heat recycling, for the reduction of production costs, for protecting air quality and for preventing pollution to the ecological environment.
Air pollution and ecological imbalance caused by the emissions of brick kilns have been major concerns in the public. Further, the waste of production cost has resulted from failure of recycling the heat energy discharged with the smoke. Referring to FIG. 1, the conventional tunnel kiln comprises a dry kiln 1, a main kiln 2, the main kiln 2 being about 120 to 150M long, and the dry kiln 1 about 100 to 120M long. The dry kiln 1 is mainly for preheating brick blanks made from clay mixed with water and additive. Such blanks are sent into the main kiln 2 for heating to become finished bricks. A heat source in the main kiln 2 comes from the combustion of coal powder, and smoke produced from the combustion will be drafted by means of the pump 201 outside the main kiln 2 for emission through the chimney 202. Because the smoke contains sulphurides and coal ashes not completely burned, it often causes the death of plants near the brick kiln, moreover it severely affects nearby air quality and is hazardous to human health, and is not consistent with modern environmental requirements. As a large amount of heat energy is discharged with smoke emission, it not only increases the burden to air quality but also increases production cost due to heat loss.
Referring to FIG. 2, an improvement is made wherein smoke is drafted by the pump 25 from preheating zone 21 and combustion zone 22 into the complete combustion zone 23 through the flue 24. When the smoke containing sulphurides and steam is released from the complete combustion zone 23, steam and sulphurides will be absorbed by the bricks (because the temperature of the completed bricks is higher than that of hot smoke). Another pump 232 is provided for drafting hot air from the complete combustion zone 23 into the dry kiln 1 for preheating the wet blanks. Most of the smoke containing residual powder will be drafted into the combustion zone 22 through the flue 24 for secondary combustion.
However, the improvements of the aforesaid are not consistent with logic and the laws of thermodynamics:
1. According to the laws of thermodynamics, high temperature flows to low temperature to reach a thermo-balance. According to the aforesaid description "for the temperature of completed bricks is higher than that of hot smoke", sulphurides and steam of the smoke will be absorbed by the bricks, which is against the laws of thermodynamics. The discharge of some steam, sulphurides and coal ashes from the completed combustion zone 23 and the discharge of some from the pump 232 into the dry kiln 1 not only will cause blackening and yellowing (due to sulphurides) of wet blanks and completed bricks, but also sulphurides, coal ashes and smoke will be discharged from the dry kiln 1 to cause air pollution, and damage to human body, and nearby vegetation. PA1 2. Residual particles of the smoke cannot be drafted to the combustion zone 22 for secondary combustion through the flue 24. Some of the smoke in the flue 24 that is discharged into the complete combustion zone 23, will be emitted from the outlet and some will be drafted by the pump 232 into the dry kiln 1.
These and other objects and advantages of the present invention will become apparent to those skilled in art after considering the following detailed specification together with the accompanying drawings.